Method of manufacturing multilayer ceramic capacitor

ABSTRACT

A method of manufacturing a multilayer ceramic capacitor includes preparing a laminate by providing ceramic layers and internal electrode layers arranged in a stacking direction, and providing two or more exposure regions at which the internal electrode layers and the ceramic layer interposed between the internal electrode layers are both exposed, and transferring a first conductive paste to the laminate. In the preparing, forming the laminate to have a rectangular parallelepiped configuration or shape and to includes two longitudinal end surfaces, and four surfaces orthogonal or substantially orthogonal to the end surfaces and, on at least one of the four surfaces, a protrusion in which the exposure region protrudes outward. In the transferring, the first conductive paste is applied to a transfer jig including a groove, and the first conductive paste in the groove is transferred to a surface of the protrusion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2017-000217 filed on Jan. 4, 2017. The entire contentsof this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method of manufacturing a multilayerceramic capacitor, a ceramic laminate, and a multilayer ceramiccapacitor.

2. Description of the Related Art

In the case of forming an external electrode on a multilayer ceramiccapacitor, there has been a known method of producing the externalelectrode by applying a conductive paste onto a surface of a laminate ofa ceramic layer and an electrode layer, which serves as an element body.As a method of applying the conductive paste onto the surface of thelaminate, there has been disclosed a method of bringing a paste wheel(transfer jig), including a groove for the conductive paste, intoabutment against the surface of the laminate fixed with a carrier tapeto transfer the conductive paste (For example, Japanese PatentApplication Laid-Open No. 2001-167989).

However, in the method described in Japanese Patent ApplicationLaid-Open No. 2001-167989, defects such as pores, pinholes, and throughholes occur at times when the transferred conductive paste is fired.FIGS. 7A and 7B are diagrams schematically showing a conventionaltechnique of transferring a conductive paste to a surface of a laminateby using a transfer jig having a groove.

As shown in FIG. 7A, in a method of filling the conductive paste in thegroove of the transfer jig and scraping off an excessive paste with asqueegee or other suitable device, the center of a conductive paste 420filled in a groove of the transfer jig 410 is sometimes recessed. Inthis case, as shown in FIG. 7B, a gap 440 is formed between theconductive paste 420 and a laminate 430 at the time of transfer, whichsometimes causes defects.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide methods ofmanufacturing multilayer ceramic capacitors in which defects, such asair bubbles, pinholes, and through holes, are not likely to occur in anexternal electrode.

A method of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention includes a laminatepreparation step of preparing a laminate including a plurality ofceramic layers and a plurality of internal electrode layers arranged ina stacking direction and including two or more exposure regions at whichthe plurality of internal electrode layers and the ceramic layerinterposed between the internal electrode layers are both exposed and atransfer step of transferring a first conductive paste to the laminate.In this manufacturing method, the laminate has a rectangular orsubstantially rectangular parallelepiped shape including two endsurfaces, which are longitudinal end surfaces, and four surfacesorthogonal or substantially orthogonal to the end surfaces and includes,on at least one of the four surfaces, a protrusion in which the exposureregion protrudes outward, in the transfer step, the first conductivepaste is applied to a transfer jig including a groove, and the firstconductive paste in the groove is transferred to a surface of theprotrusion.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, the transfer jig ispreferably a roller.

A method of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention includes a laminatepreparation step of preparing a laminate including a plurality ofceramic layers and a plurality of internal electrode layers arranged ina stacking direction and including two or more exposure regions at whichthe plurality of internal electrode layers and the ceramic layerinterposed between the internal electrode layers are both exposed, anapplication step of applying a second conductive paste onto thelaminate, and a transfer step of transferring a first conductive pasteto the laminate. In this manufacturing method, the laminate has arectangular or substantially rectangular parallelepiped shape includingtwo end surfaces, which are longitudinal end surfaces, and four surfacesorthogonal or substantially orthogonal to the end surfaces and includes,on each of two opposing surfaces of the four surfaces, a protrusion inwhich the exposure region protrudes outward, in the application step,the second conductive paste is applied onto two surfaces orthogonal orsubstantially orthogonal to the surface including the protrusion, in thetransfer step, the first conductive paste is applied to a transfer jigincluding a groove, and the first conductive paste in the groove istransferred to a surface of the protrusion.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, preferably, in thetransfer step, the first conductive paste is transferred to the surfaceincluding the protrusion so as to connect the second conductive pastes,existing on the two opposing surfaces, with each other, wherein the foursurfaces orthogonal or substantially orthogonal to the end surfaces ofthe laminate are annularly covered with the second conductive paste andthe first conductive paste.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, preferably, in theapplication step, the second conductive paste is applied so as toprotrude from a surface, orthogonal or substantially orthogonal to thesurface including the protrusion, to the surface including theprotrusion, and the second conductive paste and the first conductivepaste are brought into contact with each other on the surface includingthe protrusion, wherein the four surfaces orthogonal or substantiallyorthogonal to the end surfaces of the laminate are annularly coveredwith the second conductive paste and the first conductive paste.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, preferably, the secondconductive paste is in contact with the internal electrode layer at theprotrusion.

A ceramic laminate according to a preferred embodiment of the presentinvention includes a rectangular or substantially rectangularparallelepiped laminate including a plurality of ceramic layers and aplurality of internal electrode layers arranged in the stackingdirection and including two or more exposure regions at which theplurality of internal electrode layers and the ceramic layer interposedbetween the internal electrode layers are both exposed. In this ceramiclaminate, the laminate has a cubic or substantially cubic shapeincluding two end surfaces, which are longitudinal end surfaces, andfour surfaces orthogonal or substantially orthogonal to the end surfacesand includes, on at least one of the four surfaces, a protrusion inwhich the exposure region protrudes outward.

A multilayer ceramic capacitor according to a preferred embodiment ofthe present invention includes a rectangular or substantiallyrectangular parallelepiped laminate including a plurality of ceramiclayers and a plurality of internal electrode layers arranged in thestacking direction and including two or more exposure regions at whichthe plurality of internal electrode layers and the ceramic layerinterposed between the internal electrode layers are both exposed and afirst external electrode covering at least a portion of the laminate. Inthis multilayer ceramic capacitor, the laminate has a cubic orsubstantially cubic shape including two end surfaces, which arelongitudinal end surfaces, and four surfaces orthogonal or substantiallyorthogonal to the end surfaces and includes, on at least one of the foursurfaces, a protrusion in which the exposure region protrudes outward,and the first external electrode covers the protrusion.

In a multilayer ceramic capacitor according to a preferred embodiment ofthe present invention, preferably, second external electrodes areprovided respectively on two surfaces orthogonal or substantiallyorthogonal to the surface including the protrusion, and the firstexternal electrode is disposed such that the second external electrodesexisting on two opposing surfaces are electrically connected.

In a multilayer ceramic capacitor according to a preferred embodiment ofthe present invention, preferably, a portion of the second externalelectrode is also provided on the surface including the protrusion, andin the protrusion, the second external electrode is in contact with theinternal electrode layer.

Preferred embodiments of the present invention provide methods ofmanufacturing multilayer ceramic capacitors in which defects, such asair bubbles, pinholes, and through holes, are not likely to occur in anexternal electrode.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically showing an example of alaminate prepared by a laminate preparation step of a method ofmanufacturing a multilayer ceramic capacitor according to preferredembodiment of the present invention.

FIG. 2 is a perspective view schematically showing an example of amultilayer ceramic capacitor manufactured by a method of manufacturing amultilayer ceramic capacitor according to a preferred embodiment of thepresent invention

FIG. 3A is an LT cross-sectional view of a multilayer ceramic capacitormanufactured by a method of manufacturing a multilayer ceramic capacitoraccording to a preferred embodiment of the present invention, and FIG.3B is a WT cross-sectional view of a multilayer ceramic capacitormanufactured by a method of manufacturing a multilayer ceramic capacitoraccording to a preferred embodiment of the present invention.

FIGS. 4A and 4B are bird's eye views schematically showing examples of aceramic layer and an internal electrode layer which are a portion of alaminate prepared by a laminate preparation step of a method ofmanufacturing a multilayer ceramic capacitor according to a preferredembodiment of the present invention.

FIG. 5 is a diagram schematically showing an example of a transfer stepof a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention.

FIG. 6A is a perspective view schematically showing another example of amultilayer ceramic capacitor according to a preferred embodiment of thepresent invention, and FIG. 6B is a WT cross-sectional view of FIG. 6A.

FIGS. 7A and 7B are diagrams schematically showing a conventionaltechnique of transferring a conductive paste to a surface of a laminateby using a transfer jig having a groove.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, methods of manufacturing multilayer ceramic capacitorsaccording to preferred embodiments of the present invention will bedescribed.

However, the present invention is not limited to the configurationsdescribed below, and various modifications may be made without departingfrom the scope of the present invention. The present invention alsoencompasses a combination of two or more preferred embodiments of thepresent invention described below.

First, a non-limiting example of a multilayer ceramic capacitor obtainedby methods of manufacturing multilayer ceramic capacitors according topreferred embodiments of to the present invention will be described.

FIG. 1 is a perspective view schematically showing a non-limitingexample of a laminate prepared by a laminate preparation step of amethod of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention. FIG. 2 is a perspectiveview schematically showing an example of a multilayer ceramic capacitormanufactured by a method of manufacturing a multilayer ceramic capacitoraccording to a preferred embodiment of the present invention.

In the laminates and the multilayer ceramic capacitors according topreferred embodiments of the present invention described in the presentspecification, the length direction, the width direction, and thestacking direction are defined respectively by double-headed arrows L,W, and T in a laminate 10 shown in FIG. 1 and a multilayer ceramiccapacitor 1 shown in FIG. 2. Here, the length direction, the widthdirection, and the stacking direction are orthogonal or substantiallyorthogonal to each other. The stacking direction is the direction inwhich a plurality of ceramic layers 20 and a plurality of internalelectrode layers 30 defining the laminate 10 are stacked.

The laminate 10 preferably has a rectangular or substantiallyrectangular parallelepiped shape including a first end surface 15 and asecond end surface 16 which are longitudinal end surfaces and foursurfaces orthogonal or substantially orthogonal to the first end surface15 and the second end surface 16, and includes a plurality of stackedceramic layers 20 and a plurality of stacked internal electrode layers30. The four surfaces orthogonal or substantially orthogonal to thelongitudinal direction include two side surfaces along the stackingdirection of the laminate and two main surfaces orthogonal thereto. Thatis, the laminate 10 of the multilayer ceramic capacitor includes thefirst end surface 15 and the second end surface 16 which are thelongitudinal end surfaces, a first main surface 11 and a second mainsurface 12 which are orthogonal or substantially orthogonal to thelongitudinal end surfaces and are end surfaces in the stackingdirection, and a first side surface and a second side surface 14orthogonal or substantially orthogonal to the longitudinal end surfacesand also orthogonal or substantially orthogonal to the end surfaces inthe stacking direction.

In this specification, a cross section of the laminate 10 crossing thefirst end surface 15 and the second end surface 16 and extending alongthe stacking direction of the laminate 10 is referred to as an LT crosssection. Further, a cross section of the laminate 10 crossing the firstside surface 13 and the second side surface 14 and extending along thestacking direction of the laminate 10 is referred to as a WT crosssection.

Furthermore, a cross section of the laminate 10 which crosses the firstside surface 13, the second side surface 14, the first end surface 15,or the second end surface 16 and is orthogonal or substantiallyorthogonal to the stacking direction of the laminate 10 is referred toas an LW cross section.

The ceramic layer 20 includes outer layers 21 and an inner layer 22. Theouter layers 21 are located on the first main surface 11 side and thesecond main surface 12 side of the laminate 10 and located between theinternal electrode layers closest to one of the first main surface 11and the second main surface 12. The inner layer 22 is a regioninterposed between both outer layers 21.

Exposure regions at which the second internal electrode layer 36 and theceramic layer 20 are both exposed are provided on the first side surface13 and the second side surface 14 of the laminate 10, respectively, andthe exposure region protrudes outward from the first side surface 13 andthe second side surface 14 to define protrusions 17 and 18.

As shown in FIG. 2, in the multilayer ceramic capacitor 1, the first endsurface 15 and the second end surface 16 of the laminate 10 are coveredwith an external electrode 100, and on the first side surface 13 and thesecond side surface 14, the exposure region at which the second internalelectrode layer 36 and the ceramic layer 20 are both exposed is coveredwith an external electrode 200 (first external electrode).

Subsequently, with reference to FIGS. 3A, 3B, 4A, and 4B, the ceramiclayer, the internal electrode layer, the protrusion, and the externalelectrode defining the multilayer ceramic capacitor manufactured by amethod of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention will be described.

FIG. 3A is an LT cross-sectional view of the multilayer ceramiccapacitor manufactured by the method of manufacturing a multilayerceramic capacitor according to a preferred embodiment of to the presentinvention, and is also a cross-sectional view along line A-A in FIG. 2.FIG. 3B is a WT cross-sectional view of the multilayer ceramic capacitormanufactured by the method of manufacturing a multilayer ceramiccapacitor according to a preferred embodiment of the present invention,and is also a cross-sectional view along line B-B in FIG. 2.

FIGS. 4A and 4B are bird's eye views schematically showing examples ofthe ceramic layer and the internal electrode layer which are a portionof the laminate prepared by the laminate preparation step of the methodof manufacturing a multilayer ceramic capacitor according to a preferredembodiment of the present invention.

As shown in FIGS. 3A and 3B, the plurality of internal electrode layers30 include a first internal electrode layer 35 and a second internalelectrode layer 36 arranged in the stacking direction.

The first internal electrode layer 35 and the ceramic layer 20 are bothexposed on both of the first end surface 15 and the second end surface16. The second internal electrode layer 36 and the ceramic layer 20 areboth exposed on both of the first side surface 13 and the second sidesurface 14 to define an exposure region. Electrostatic capacitance isgenerated at an opposing electrode portion at which the first internalelectrode layer 35 and the second internal electrode layer 36 face eachother with the ceramic layer 20 interposed therebetween.

As shown in FIG. 3B, the second internal electrode layer 36 and theceramic layer 20 are both exposed on both of the first side surface 13and the second side surface 14 to define an exposure region, and theexposure region protrudes outward to define the projections 17 and 18.The protrusion 17 protrudes from the first side surface 13 by a lengthindicated by a double-headed arrow X₁.

The protrusion is covered with the first external electrode. As thefirst external electrode covering the protrusion, typical externalelectrodes used for multilayer ceramic capacitors may be used.

As shown in FIG. 4A, the first internal electrode layer 35 preferablyincludes the opposing electrode portion at which the first internalelectrode layer 35 and the second internal electrode layer 36 face eachother with the ceramic layer 20 interposed therebetween, and an extendedelectrode portion extending out from the opposing electrode portion tothe first end surface 15. On the first end surface 15 and the second endsurface 16, the first internal electrode layer 35 is exposed. As shownin FIG. 4B, the second internal electrode layer 36 preferably includesan opposing electrode portion facing the opposing electrode portion ofthe first internal electrode layer 35 with the ceramic layer 20interposed therebetween, and an extended electrode portion extending outfrom the opposing electrode portion to the first side surface 13 and thesecond side surface 14. On the first side surface 13 and the second sidesurface 14, an exposure region in which the second internal electrodelayer 36 is exposed is provided.

In FIGS. 4A and 4B, portions corresponding to the protrusions 17 and 18are preferably provided in advance at respective portions correspondingto the first side surface 13 and the second side surface 14. However, inthe laminate preparation step in the method of manufacturing amultilayer ceramic capacitor according to a preferred embodiment of thepresent invention, it is not necessary that a ceramic green sheet has ashape as shown in FIGS. 4A and 4B. For example, a method of stacking aplurality of rectangular or substantially rectangular ceramic greensheets including no protrusion to form a laminate and then forming aprotrusion may be used.

As the ceramic layer, a perovskite compound typified by barium titanate(BaTiO₃) and represented by the general formula AmBO₃ may preferably beused (the A site is Ba and may include, besides Ba, at least oneselected from the group consisting of Sr and Ca; the B site is Ti andmay include, besides Ti, at least one selected from the group consistingof Zr and Hf; O is oxygen; m is the molar ratio between the A site andthe B site). A ceramic material primarily composed of calcium titanate(CaTiO₃), strontium titanate (SrTiO₃), calcium zirconate (CaZrO₃) orother suitable materials may preferably be used, for example. Inaddition, each of the ceramic layers may preferably include, forexample, Mn, Mg, Si, Co, Ni, V, Al, a rare earth element or othersuitable materials as a subcomponent whose content is smaller than thatof the main component.

It is preferable that the internal electrode layer includes at least oneselected from the group consisting of Cu, Ni, Ag, Pd, Ag—Pd alloy andAu, for example. It is also preferable that the internal electrode layerincludes a dielectric material having the same or substantially the samecomposition as the ceramic material contained in the ceramic layer.

A description will next be made of a method, according to a preferredembodiment of the present invention, of manufacturing theabove-described multilayer ceramic capacitor.

The method includes a laminate preparation step of preparing a laminateand a transfer step of transferring a first conductive paste to aprotrusion of the laminate.

In the laminate preparation step, a laminate including a plurality ofceramic layers and a plurality of internal electrode layers arranged inthe stacking direction is prepared.

The laminate has a rectangular or substantially rectangularparallelepiped shape including two end surfaces, which are longitudinalend surfaces, and four surfaces orthogonal or substantially orthogonalto the end surfaces, two or more exposure regions at which the internalelectrode layer and the ceramic layer interposed between the internalelectrode layers are both exposed.

The laminate prepared in the laminate preparation step is also a ceramiclaminate according to a preferred embodiment of the present invention.

Examples of a method of preparing such a laminate include a method ofstacking a predetermined number of ceramic green sheets to be ceramiclayers and on which an internal electrode pattern to be an internalelectrode layer is formed, compressing the laminate to form a greensheet laminate, and then compressing and firing the green sheetlaminate.

For example, the ceramic green sheet may preferably be obtained by, forexample, applying a ceramic slurry, mixed with ceramic to be a rawmaterial of a ceramic layer, an organic matter, a solvent, and othersuitable ingredients, onto a carrier film, such as a PET film, into asheet by spray coating, die coating, screen printing, or other suitablemethod.

The thickness of the ceramic green sheet is preferably not less thanabout 0.4 μm and not more than about 3.0 μm, for example.

The same ceramic as the raw material defining the ceramic layer in themultilayer ceramic capacitor described above be suitably used for theceramic to be a raw material of the ceramic slurry.

The conductive paste to be the internal electrode layer is preferablyformed of a metal material such as Ni powders, a solvent, a dispersingagent and a binder, and the internal electrode pattern may be formed byprinting on a ceramic green sheet by screen printing, gravure printingor other suitable method.

The thickness of the printed internal electrode pattern is preferablynot less than about 0.4 μm and not more than about 0.7 μm, for example.

Examples of a method of compressing the green sheet laminate includerigid pressing and isostatic pressing.

At the time of pressing, when a resin sheet having a constant orapproximately constant thickness is disposed as the outermost layer,sufficient pressure is applied to a portion including no internalelectrode pattern, so that an adhesive force between the ceramic greensheets is improved.

The number of ceramic layers defining the green sheet laminate ispreferably not less than 100 and not more than 1000, for example. Thenumber of ceramic layers does not include the number of ceramic layersdefining an outer layer.

Among the ceramic layers, each ceramic layer defining an inner layerpreferably has a thickness of not less than about 0.5 μm and not morethan about 1.0 μm, for example. The thickness of the outer layer ispreferably not less than about 15 μm and not more than about 70 μm onone side, for example.

Each dimension of the laminate as described above may be measured by amicrometer, and the number of ceramic layers may be counted using anoptical microscope.

Thereafter, the obtained green sheet laminate is compressed, and ifnecessary, cut out such that the internal electrode layer and theceramic layer interposed between the internal electrode layers are bothexposed at four places (both end surfaces and both side surfaces), andthis green sheet laminate is fired under predetermined conditions toobtain a laminate. It is preferable to perform barrel polishing in whichthe green sheet laminate cut into a predetermined shape and a polishingagent are placed in a barrel and a corner portion and a ridgelineportion of the laminate are rounded by applying rotational motion to thebarrel.

Next, a method of forming a protrusion on a laminate will be described.

The laminate prepared in the laminate preparation step further includesa protrusion in which the exposure region protrudes outward on at leastone of four surfaces orthogonal or substantially orthogonal to the endsurfaces.

Examples of a method of obtaining such a laminate include a method ofproducing a rectangular or substantially rectangular parallelepipedlaminate with the use of a rectangular or substantially rectangularceramic green sheet having no convex portion and having a shapecorresponding to the protrusion, applying a masking agent to a sidesurface of this laminate, and then applying blasting treatment to theside surface to scrape other regions than a region to be the protrusion.

Examples of a blasting material used for the blasting treatment includesteel, stainless steel, zirconia, alumina, silica, silicon carbide andthe like, resin, and rubber.

The shape of the blasting material may be spherical or non-spherical.

The blasting treatment may be dry blasting or wet blasting.

As a method of forming a protrusion on a laminate, in addition to theabove-described method, it is also possible to use a method of preparinga ceramic green sheet having such a shape (for example, a shape shown inFIGS. 4A and 4B) that the protrusion is formed in advance and stackingthe ceramic green sheet to produce a laminate.

Although the protruding height of the protrusion is not particularlylimited, it is preferably not less than about 1 μm and not more thanabout 10 μm, for example.

If the protruding height of the protrusion is less than about 1 μm, airbubbles are likely to be formed when a conductive paste is transferred,so that defects such as pores, pinholes, and through holes are likely tobe formed in the external electrode.

On the other hand, if the protruding height of the protrusion is morethan about 10 μm, the proportion of the protrusion in the wholemultilayer ceramic capacitor increases, and an electrostatic capacitanceper volume decreases.

The laminate including the protrusion formed thereon is a ceramiclaminate of a preferred embodiment of the present invention, and thefirst conductive paste is transferred to the protrusion of the ceramiclaminate to be fired, and thus, to form the first external electrode,such that the multilayer ceramic capacitor is obtained.

Since the ceramic laminate includes the protrusion in which the exposureregion at which the internal electrode layer and the ceramic layerinterposed between the internal electrode layers are both exposedprotrudes, when the external electrode is formed by transferring theconductive paste, defects such as pores, pinholes, and non-through holesare not likely occur in the external electrode.

Subsequently, the transfer step of transferring the first conductivepaste to the protrusion will be described.

In the transfer step, the first conductive paste is applied to atransfer jig including a groove, and the conductive paste in the grooveis transferred to a surface of the protrusion.

Since a region to be transferred with the first conductive pasteprotrudes toward the conductive paste, even in a case in which the firstconductive paste in the groove of the transfer jig is concave as in theconventional technique, a gas is prevented from being caught between theprotrusion and the first conductive paste.

Accordingly, a pinhole is not likely to occur in the first externalelectrode formed by firing the first conductive paste.

The transfer step will be described with reference to FIG. 5.

FIG. 5 is a diagram schematically showing an example of the transferstep of the method of manufacturing a multilayer ceramic capacitoraccording to a preferred embodiment of the present invention.

In the transfer step shown in FIG. 5, the laminate 10 fixed with acarrier tape 300 indicated by a two-dot chain line passes betweentransfer jigs 310 rotating in different directions. Arrows on the upperand lower sides of the carrier tape 300 indicate directions in which thecarrier tape 300 and the laminate 10 move, and arrows at the centralportions of the transfer jigs 310 indicate the rotating directions ofthe transfer jigs 310.

When the laminate 10 passes between the transfer jigs 310, the surfaceson which the protrusions 17 and 18 are formed come into contact with thetransfer jigs 310, and the first conductive paste 320 filled in a grooveon a surface of a transfer jig 310 is transferred. The transfer jig 310is rotating in a predetermined direction, and the transfer jig 310 firstcomes into contact with the first conductive paste 320, so that thefirst conductive paste 320 adheres to the surface of the transfer jig310 and is filled in the groove. Thereafter, the first conductive paste320 other than one filled in the groove is scraped off by a squeegee350. At this time, as shown in FIG. 7A, although it is considered that arecess is formed in a surface of the first conductive paste 320, theprotrusions 17 and 18 are formed on the surface of the laminate 10, sothat the conductive paste 320 is transferred without formation of airbubbles between the laminate 10 and the conductive paste 320.

When the surfaces of the squeegee and the transfer jig are elasticbodies, recesses tend to be formed in the surface of the conductivepaste, which is more effective.

The type of the transfer jig is only required to be able to transfer thefirst conductive paste to the surface of the laminate, and for example,a roller including a groove may preferably be used.

The material used for the transfer jig is not particularly limited, andmetal, such as stainless steel or an elastic body such as SBR rubber,urethane rubber, or silicone rubber, for example, may preferably beused.

In order to scrape off the extra first conductive paste applied to thetransfer jig, a squeegee may preferably be used.

The type of the squeegee is not particularly limited, and a flatsqueegee, a sword squeegee, a round squeegee, an angular squeegee, orother suitable squeegee, may preferably be used.

Although the material used for the squeegee is not particularly limited,metal, silicone rubber, acrylic resin or other suitable materials, forexample, may preferably be used, and a plurality of materials may beused in combination.

It is preferable that a contact angle between the squeegee and thetransfer jig is suitably set according to the viscosity of the firstconductive paste, a contact condition (contact angle, speed, etc.)between the transfer jig and the laminate.

Although the depth of the groove provided in the transfer jig is notparticularly limited, it is preferably not less than about 5 μm and notmore than about 50 μm, for example.

The shape of the groove provided in the transfer jig is not particularlylimited, and it may be a square shape, a trapezoidal shape, a U shape orother suitable shape, for example.

In the transfer step, although the first conductive paste may betransferred by bringing the transfer jig into contact with only onesurface of the laminate, it is preferable that two transfer jigs aresimultaneously brought into contact with two opposing surfaces totransfer the first conductive paste.

The first conductive paste includes metal and glass and, if necessary,may include a resin.

The first conductive paste preferably includes at least one metalselected from the group consisting of Cu, Ni, Ag, Pd, Ag—Pd alloy andAu, for example.

It is possible to use glass, such as B—Si based glass, B—Si—Zn basedglass, B—Si—Zn—Ba based glass, and B—Si—Zn—Ba—Ca—Al based glass, forexample.

By virtue of the above-described method, it is possible to obtain amultilayer ceramic capacitor includes a rectangular or substantiallyrectangular parallelepiped laminate including a plurality of ceramiclayers and a plurality of internal electrode layers arranged in thestacking direction, and two or more exposure regions at which theplurality of internal electrode layers and the ceramic layer interposedbetween the internal electrode layers are both exposed and the firstconductive paste layer covering at least a portion of the laminate. Inthe multilayer ceramic capacitor, the laminate has a cubic orsubstantially cubic shape including two end surfaces as longitudinal endsurfaces and four surfaces orthogonal or substantially orthogonal to theend surfaces and includes, on at least one of the four surfaces, aprotrusion in which the exposure region protrudes outward, and the firstconductive paste layer covers the protrusion.

In the ceramic laminate, since the first conductive paste layer coversthe protrusion on the side surface of the laminate, air bubbles,pinholes, through holes, and other defects are less likely to be formedbetween the first conductive paste and the laminate. Accordingly, amultilayer ceramic capacitor in which connection between the internalelectrode layer and the external electrode is stable and reliable isable to be obtained by firing such a ceramic laminate.

A multilayer ceramic capacitor in which the first conductive paste layeris the first external electrode may be obtained by firing the obtainedceramic laminate at a predetermined temperature. The multilayer ceramiccapacitor manufactured by such a method is also included as a preferredembodiment of the present invention.

Although the thickness of the first external electrode covering theprotrusion is not particularly limited, it is preferably not less thanabout 20 μm and not more than about 50 μm, for example. The thickness ofthe first external electrode covering the protrusion is indicated by themaximum height from a surface where the protrusion exists.

A method of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention may further include anapplication step.

In the application step, a second conductive paste is applied to twosurfaces (a first main surface and a second main surface) orthogonal orsubstantially orthogonal to a surface including a protrusion (a firstside surface and/or a second side surface).

In a laminate in which protrusions are formed on respective two opposingsurfaces, when the application step is applied to a surface of thelaminate including no protrusion, a conductive paste is applied to allfour surfaces of the laminate other than the end surfaces of thelaminate.

Although the order of the application step and the transfer step is notparticularly limited, the application step is preferably performedbefore the transfer step.

This is because when the application step is performed before thetransfer step, it is possible to reduce an area to which the firstconductive paste is transferred in the transfer step.

At this time, it is preferable to transfer and apply the conductivepaste such that the first conductive paste and the second conductivepaste are in contact with each other.

When the first conductive paste and the second conductive paste arebrought into contact with each other, the conductive paste is applied toannularly cover the four surfaces orthogonal or substantially orthogonalto the end surfaces of the laminate. When the conductive pastes are incontact with each other, since external electrodes after firing areelectrically connected to each other, an external electrode annularlycovering four surfaces orthogonal or substantially orthogonal to the endsurfaces of a multilayer ceramic capacitor is formed, and the multilayerceramic capacitor is able to be easily mounted.

As a method of applying the second conductive paste, although a methodsimilar to that for the first conductive paste may be used, a methodconventionally used to form an external electrode may preferably beused, for example.

Since an internal electrode layer is not formed on a surface to whichthe second conductive paste is to be applied, even if a defect such as apinhole occurs, there is no particular problem.

That is, among the four surfaces orthogonal or substantially orthogonalto the end surfaces of the laminate, a protrusion may be formed on onlythe surface (side surface) at which the internal electrode layer and theceramic layer interposed between the internal electrode layers are bothexposed, and no protrusion may be formed on two surfaces (main surfaces)orthogonal or substantially orthogonal to the surface at which theinternal electrode layer and the ceramic layer interposed between theinternal electrode layers are both exposed.

The laminate to be subjected to the application step may be a laminatein which protrusions are formed on at least one of the four surfacesorthogonal or substantially orthogonal to the end surfaces, and may be alaminate in which the protrusions are formed on respective two opposingsurfaces of the four surfaces orthogonal or substantially orthogonal tothe end surfaces. However, the laminate to be subjected to theapplication step is preferably a laminate in which the protrusions areformed on the two opposing surfaces.

The protrusions are formed on the respective two opposing surfaces ofthe four surfaces orthogonal or substantially orthogonal to the endsurfaces, and when the second conductive paste is applied to cover thesurfaces orthogonal or substantially orthogonal to the surfaces on whichthe protrusions are formed, all of the four surfaces orthogonal orsubstantially orthogonal to the end surfaces of the laminate can becovered with the conductive paste.

Although a target surface to which the second conductive paste isapplied is not a surface including the protrusion, in the applicationstep, it is preferable to apply the second conductive paste also to thesurface including the protrusion. That is, in a method of manufacturinga multilayer ceramic capacitor according to a preferred embodiment ofthe present invention, preferably, in the application step, the secondconductive paste is applied so as to protrude from a surface, orthogonalor substantially orthogonal to the surface including the protrusion, tothe surface including the protrusion, and the second conductive pasteand the first conductive paste are brought into contact with each otheron the surface including the protrusion, such that the four surfacesorthogonal or substantially orthogonal to the end surfaces of thelaminate are annularly covered with the second conductive paste and thefirst conductive paste.

In the application step, when the second conductive paste is applied soas to protrude from the surface orthogonal or substantially orthogonalto the surface including the protrusion to the surface including theprotrusion, in the case in which the four surfaces orthogonal orsubstantially orthogonal to the end surfaces of the laminate areannularly covered with the second conductive paste and the firstconductive paste, a region to which the first conductive paste should betransferred is reduced, and therefore, air bubbles are less likely to beformed between the first conductive paste and the protrusion in thetransfer step.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, more preferably, thesecond conductive paste is in contact with the internal electrode layerat the protrusion.

When the second conductive paste is in contact with the internalelectrode layer at the protrusion, the region to which the firstconductive paste should be transferred is reduced, and therefore, airbubbles are less likely to be formed between the first conductive pasteand the protrusion in the transfer step.

The configuration of another example of a multilayer ceramic capacitoraccording to a preferred embodiment of the present invention will bedescribed with reference to FIGS. 6A and 6B.

FIG. 6A is a perspective view schematically showing another example ofthe multilayer ceramic capacitor, and FIG. 6B is a WT cross-sectionalview of FIG. 6A. FIG. 6B is also a cross-sectional view along line C-Cin FIG. 6A

As shown in FIG. 6A, longitudinal end surfaces of the laminate 10 of amultilayer ceramic capacitor 2 are covered with the external electrode100, and an external electrode 200 annularly covering four surfaces isprovided on four surfaces orthogonal or substantially orthogonal to thelongitudinal direction.

As shown in FIG. 6B, the external electrode 200 is defined by firstexternal electrodes 210, which cover the surfaces 13 and 14 includingthe protrusions 17 and 18 in which an exposure region at which theinternal electrode layer 30 and the ceramic layer 20 are both exposedprotrudes outward, and second external electrodes 220 covering the twosurfaces 11 and 12 orthogonal or substantially orthogonal to the surfaceon which the protrusion is provided.

A portion of the second external electrode 220 is also provided on thesurfaces 13 and 14 on which the protrusions 17 and 18 are provided, andthe first external electrodes 210 connect the second external electrodes220 to each other and cover the protrusions 17 and 18. The secondexternal electrode 220 is in contact with the second internal electrodelayer 36 at the protrusions 17 and 18.

Examples of a method as shown in FIG. 6B of forming the second externalelectrodes 220 on not only the two surfaces 11 and orthogonal orsubstantially orthogonal to the surfaces including the protrusions 17and 18 but also the surfaces 13 and including the protrusions 17 and 18include a method as described above in which in the application step,the second conductive paste is applied so as to protrude from thesurface, orthogonal or substantially orthogonal to the surface includingthe protrusion, to the surface including the protrusion, and fired.

A method of manufacturing a multilayer ceramic capacitor according to apreferred embodiment of the present invention may include a step offorming an external electrode on the end surface of the laminate.Although a method of forming the external electrode on the end surfaceof the laminate is not particularly limited, a method in which aconductive paste is applied to the end surface of the laminate and firedmay preferably be used.

The conductive paste for forming the external electrode at an end of thelaminate is not particularly limited, and one of the first conductivepaste and the second conductive paste may be used, and a conductivepaste having a different composition from those of the first conductivepaste and the second conductive paste may be used.

There is no particular limitation on the order of the step of formingthe external electrode on the end surface of the laminate and thetransfer step, and either one may be performed first.

In a method of manufacturing a multilayer ceramic capacitor according toa preferred embodiment of the present invention, a plating layer maypreferably further be formed on a surface of the external electrodeobtained by firing the conductive paste.

Although the composition of the plating layer formed on the surface ofthe external electrode is not particularly limited, it preferablyincludes at least one selected from the group consisting of Cu, Ni, Ag,Pd, Ag—Pd alloy, Au and Sn, for example, and two or more layers havingdifferent compositions may be stacked.

As the plating layer including two or more layers, a plating layerincluding a nickel plating layer (first layer) in direct contact withthe external electrode and a tin plating layer (second layer) not indirect contact with the external electrode, for example, is preferable.

It is preferable that the thickness of the nickel layer is not less thanabout 1 μm and not more than about 8 μm, and the thickness of the tinlayer is not less than about 1 μm and not more than about 8 μm, forexample.

When the nickel plating layer is formed, it is possible to reduce orprevent erosion of the external electrode due to solder when themultilayer ceramic capacitor is mounted. When the tin plating layer isformed, solder wettability is improved, so that the multilayer ceramiccapacitor is able to be easily mounted.

Hereinafter, examples specifically showing multilayer ceramic capacitorsaccording to preferred embodiments of the present invention will bedescribed. The present invention is not limited to only these examples.

Example 1

A polyvinyl butyral type binder, a plasticizer, and ethanol as anorganic solvent were added to BaTiO₃ as a ceramic raw material, and theywere wet mixed by a ball mill to produce a ceramic slurry. Then, thisceramic slurry was formed into a sheet by a lip method to obtain arectangular or substantially rectangular ceramic green sheet. Then, aconductive paste including Ni was screen-printed on the ceramic greensheet to form an internal electrode pattern primarily composed of Ni.Then, a plurality of the ceramic green sheets including the internalelectrode patterns formed thereon were stacked such that the directionsin which the internal electrode layers were extended out were orthogonalor substantially orthogonal to each other, to obtain a green laminatesheet to be a capacitor body. Then, this green laminate sheet waspressure molded and divided by dicing to obtain chips. The obtainedchips were heated at about 1200° C. in an N₂ atmosphere to burn a binderand then fired in a reducing atmosphere containing H₂, N₂ and H₂O gasesto obtain a sintered laminate. The structure of the laminate is astructure including a plurality of ceramic layers and a plurality ofinternal electrode layers.

The average thickness of the internal electrode layers was about 0.55μm, the average thickness of the ceramic layers interposed between theinternal electrode layers was about 0.65 μm, and the number of theinternal electrode layers was 560.

The dimensions of the laminate were about 1.13 mm in L direction X about0.85 mm in W direction X about 0.75 mm in T direction. An exposureregion at which the first internal electrode layer and the ceramic layerinterposed between the first internal electrode layers were exposed onthe first end surface and the second end surface, which were endsurfaces in the L direction, was formed, and an exposure region at whichthe second internal electrode layer and the ceramic layer interposedbetween the second internal electrode layers were exposed on the firstside surface and the second side surface, which are end surfaces in theW direction, was formed. The length in the L direction in the exposureregion of the second internal electrode layer was about 300 μm. Barrelpolishing was applied to this laminate to round corners of the laminate.

Thereafter, a masking agent was applied to surfaces of the exposureregions on the first side surface and the second side surface at whichthe second internal electrode layer and the ceramic layer were exposed,and blasting treatment was performed using a zirconia powder, such thata ceramic laminate according to Example 1, in which protrusions wereformed on the first side surface and the second side surface wasobtained.

After solidifying the obtained ceramic laminate with a resin, a WTsurface was polished to half the length in the L direction to expose theWT surface. The WT surface was observed at a magnification of 1000 timesusing a microscope, and the maximum thickness of the protrusion wasmeasured. The same operation was performed with 10 samples, and theaverage value thereof was taken as the protruding height of theprotrusion, so that the protruding height was about 1 μm.

Then, a mixture of copper grains and glass was dispersed in a solvent toproduce a first conductive paste.

The viscosity of the first conductive paste was about 60 Pa·s.

Two rubber rollers including linear grooves with a width of about 440 μmand a depth of about 40 μm provided on the surface were prepared astransfer jigs and arranged as shown in FIG. 5. The rubber roller was incontact with the first conductive paste in the lower portion and wasconfigured such that the first conductive paste was continuouslysupplied to the rubber roller by rotating. The first conductive pastesupplied to the rubber roller was configured such that portions otherthan the groove portion were scraped off by a metal squeegee.

The two transfer jigs as described above were arranged to face eachother, and while the transfer jigs were rotated in different directions,a ceramic laminate fixed to a carrier tape was passed through a gapbetween the rotating transfer jigs. Consequently, the first conductivepaste was transferred from the transfer jig to the surface of theprotrusion. Since the width of the groove in the surface of the transferjig is larger than the length in the L direction in the exposure regionof the second internal electrode layer, the exposure region of thesecond internal electrode layer was covered with the first conductivepaste. Thereafter, firing was performed at about 850° C. to form a firstexternal electrode.

Subsequently, the first end surface and the second end surface wereimmersed in a conductive paste having the same or substantially the samecomposition as that of the first conductive paste used in the transferstep, such that the conductive paste was applied to the first endsurface and the second end surface. By firing this, external electrodeswere also formed on the first end surface and the second end surface.

Thereafter, nickel plating (thickness: about 4 μm) and tin plating(thickness: about 4 μm) were applied in this order onto the externalelectrodes formed on the first end surface, the second end surface, thefirst side surface, and the second side surface.

Through the above step, the multilayer ceramic capacitor according toExample 1 was produced.

Examples 2 to 4

Multilayer ceramic capacitors according to Examples 2 to 4 were producedin the same or substantially the same procedure as in Example 1 exceptthat the protruding height of the protrusion was changed by adjustingthe time of the blasting treatment in the laminate preparation step.

Comparative Example 1

In the laminate preparation step, a multilayer ceramic capacitoraccording to Comparative Example 1 was produced in the same orsubstantially the same procedure as in Example 1 except that the blasttreatment was not performed.

Comparative Examples 2 to 3

In the laminate preparation step, multilayer ceramic capacitorsaccording to Comparative Examples 2 to 3 were produced in the same orsubstantially the same procedure as in Example 1 except that a maskingagent was applied to a portion other than the exposure region on thefirst side surface and the second side surface at which the secondinternal electrode layer and the ceramic layer interposed between thesecond internal electrode layers were both exposed, and blastingtreatment was performed, such that the exposure region was scraped toform a recess (the protruding height of the protrusion was madenegative).

After solidifying the multilayer ceramic capacitors according toExamples 1 to 4 and Comparative Examples 1 to 3 with a resin, the WTsurface was polished to half the length in the L direction to expose theWT surface. The first external electrode formed on the surface of theprotrusion was observed with a microscope, and the presence or absenceof air bubbles and pinholes having a diameter of not less than about 15μm was confirmed. Among 1000 multilayer ceramic capacitors, those havingair bubbles, pinholes or through holes were counted as defectiveproducts, and the percent defective was measured. The results are shownin Table 1.

TABLE 1 Protruding height of protrusion Percent [μm] defective Example 11 0.1% Example 2 4 0.0% Example 3 5 0.0% Example 4 7 0.0% Comparative 00.5% Example 1 Comparative −1 0.8% Example 2 Comparative −3 1.0% Example3

Example 5

A multilayer ceramic capacitor according to Example 5 was produced inthe same or substantially the same procedure as in Example 1 except thatthe following application step was performed before the transfer step.

Among four surfaces orthogonal or substantially orthogonal to endsurfaces of a ceramic laminate, the second conductive paste wastransferred (applied) to a surface (first main surface and second mainsurface) having no protrusion with the use of the transfer jig used inthe transfer step, and the second conductive paste was dried at about170° C. At this time, a force with which the transfer jig pressed thelaminate was adjusted, such that the second conductive paste was alsoapplied to the surface on which the protrusion was formed. Thetransferred second conductive paste was in contact with the internalelectrode layer defining the protrusion. The second conductive pastehaving the same or substantially the same composition as that of thefirst conductive paste was used.

Examples 6 to 8

Multilayer ceramic capacitors according to Examples 6 to 8 were producedin the same or substantially the same procedure as in Example 5 exceptthat the protruding height of the protrusion was changed by adjustingthe time of the blasting treatment in the laminate preparation step.

Comparative Example 4

In the laminate preparation step, a multilayer ceramic capacitoraccording to Comparative Example 1 was produced in the same orsubstantially the same procedure as in Example 5 except that the blasttreatment was not performed.

Comparative Examples 5 to 6

In the laminate preparation step, multilayer ceramic capacitorsaccording to Comparative Examples 5 to 6 were produced in the same orsubstantially the same procedure as in Example 5 except that a maskingagent was applied to a portion other than the exposure region on thefirst side surface and the second side surface where the second internalelectrode layer and the ceramic layer interposed between the secondinternal electrode layers were exposed, and blasting treatment wasperformed, such that the exposure region was scraped to form a recess(the protruding height of the protrusion was made negative).

For the multilayer ceramic capacitors of Examples 5 to 8 and ComparativeExamples 4 to 6, the first external electrode was observed in the sameor substantially the same procedure as in Examples 1 to 4 andComparative Examples 1 to 3. Among 1000 multilayer ceramic capacitors,those having pores, pinholes or through holes were counted as defectiveproducts, and the percent defective was measured. The results are shownin Table 2.

TABLE 2 Protruding height of protrusion Percent [μm] defective Example 51 0.2% Example 6 4 0.0% Example 7 5 0.0% Example 8 7 0.0% Comparative 00.9% Example 4 Comparative −1 1.5% Example 5 Comparative −3 2.0% Example6

From the results of Tables 1 and 2, it was confirmed that the occurrenceof defects such as air bubbles, pinholes, and through holes in theexternal electrode is reduced or prevented according to methods ofmanufacturing multilayer ceramic capacitors according to preferredembodiments of the present invention.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A method of manufacturing a multilayer ceramiccapacitor, the method comprising: preparing a laminate by providing aplurality of ceramic layers and a plurality of internal electrode layersarranged in a stacking direction, providing two or more exposure regionsat which the plurality of internal electrode layers and the ceramiclayer interposed between the plurality of internal electrode layers areboth exposed, and forming the laminate to have a rectangularparallelepiped configuration or shape; and transferring a firstconductive paste to the laminate; wherein the laminate having therectangular parallelepiped configuration or shape further including twoend surfaces, which are longitudinal end surfaces, and four surfacesorthogonal to the end surfaces and includes, on at least one of the foursurfaces, a protrusion in which the exposure region protrudes outward;and in the transferring, the first conductive paste is applied to atransfer jig including a groove, and the first conductive paste in thegroove is transferred to a surface of the protrusion.
 2. The method ofmanufacturing a multilayer ceramic capacitor according to claim 1,wherein the transfer jig includes a roller.
 3. The method ofmanufacturing a multilayer ceramic capacitor according to claim 1,wherein the plurality of ceramic layers are made of a perovskitecompound.
 4. The method of manufacturing a multilayer ceramic capacitoraccording to claim 1, wherein the plurality of internal electrode layersinclude at least one selected from the group consisting of Cu, Ni, Ag,Pd, Ag—Pd alloy and Au.
 5. The method of manufacturing a multilayerceramic capacitor according to claim 1, wherein a height of theprotrusion is not less than 1 μm and not more than 10 μm.
 6. A method ofmanufacturing a multilayer ceramic capacitor, the method comprising:preparing a laminate by providing a plurality of ceramic layers and aplurality of internal electrode layers arranged in a stacking direction,providing two or more exposure regions at which the plurality ofinternal electrode layers and the ceramic layer interposed between theinternal electrode layers are both exposed, and forming the laminate tohave a rectangular parallelepiped configuration or shape; applying asecond conductive paste onto the laminate; and transferring a firstconductive paste to the laminate; wherein the laminate having therectangular parallelepiped configuration or shape further including twoend surfaces, which are longitudinal end surfaces, and four surfacesorthogonal to the end surfaces and includes, on each of two opposingsurfaces of the four surfaces, a protrusion in which the exposure regionprotrudes outward; in the applying, the second conductive paste isapplied onto two surfaces orthogonal to the surface including theprotrusion, respectively; and in the transferring, the first conductivepaste is applied to a transfer jig including a groove, and the firstconductive paste in the groove is transferred to a surface of theprotrusion.
 7. The method of manufacturing a multilayer ceramiccapacitor according to claim 6, wherein the transfer jig includes aroller.
 8. The method of manufacturing a multilayer ceramic capacitoraccording to claim 6, wherein in the transferring, the first conductivepaste is transferred to the surface including the protrusion so as toconnect the second conductive pastes existing on the two opposingsurfaces with each other; and the four surfaces orthogonal to the endsurfaces of the laminate are annularly covered with the secondconductive paste and the first conductive paste.
 9. The method ofmanufacturing a multilayer ceramic capacitor according to claim 6,wherein in the applying, the second conductive paste is applied so as toprotrude from a surface orthogonal to the surface including theprotrusion to the surface including the protrusion, and the secondconductive paste and the first conductive paste are brought into contactwith each other on the surface including the protrusion, and the foursurfaces orthogonal to the end surfaces of the laminate are annularlycovered with the second conductive paste and the first conductive paste.10. The method of manufacturing a multilayer ceramic capacitor accordingto claim 9, wherein the second conductive paste is in contact with theinternal electrode layer at the protrusion.
 11. The method ofmanufacturing a multilayer ceramic capacitor according to claim 6,wherein the plurality of ceramic layers are made of a perovskitecompound.
 12. The method of manufacturing a multilayer ceramic capacitoraccording to claim 6, wherein the plurality of internal electrode layersinclude at least one selected from the group consisting of Cu, Ni, Ag,Pd, Ag—Pd alloy and Au.
 13. The method of manufacturing a multilayerceramic capacitor according to claim 6, wherein a height of theprotrusion is not less than 1 μm and not more than 10 μm.